Apparatus for measuring density of circulating fluid



Jan. 11, 1944. o. E. STONER APPARATUS FOR MEASURING DENSITY OF CIRCULATING FLUID Filed March 21, 1940 2 Sheets-Sheet 1 Inventor OSCAR E. ST NER,

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Jan. 11, 1944.

O. E. STONER APPARATUS FOR MEASURING DENSITY OF CIRCULATING FLUID Filed March 21, 1940 2 Sheets-Sheet 2 ln venior QSCAR E. STONER,

Attorneys Patented Jan. 11, 1944 APPARATUS FOR MEASURING DENSITY OF CIRCULATING FLUID Oscar E. Stoner, Tulsa, Okla.

Application March 21, 1940, Serial No. 325,233

2 Claims.

The principal object of the present invention is to provide a device adapted to automatically and continually measure and record the weight or density of a circulating fluid, and more particularly the drilling-mud or other liquid mixtures used in well drilling.

Wells or bore holes drilled by the rotary method use a rotary bit on a string of drill pipe to drill the hole and a circulating column of mud or other drilling fluid to remove the drill cuttings and prevent the hole from caving in. In this operation, it is often necessary to know what the weight or density of the drilling fluid is. The weight must be suflicient to exert pressure to overcome any pressures of underground flows of thus cause the drilling fluid to penetrate back into oil or gas strata and seal them. Excessive pressure also 'may result in the drilling fluid being forced back into porous strata with a resulting loss of circulation which is one of the greatest hazards of drilling. Hence, the proper control of the weight of drilling fluid is necessary to prevent blow-outs and/or loss of circulation either of which could result in complete loss of the drilling well.

It is the principal object of the present invention to provide means for automatically determining and recording the weight of the drilling mud continually and at all times.

Other objects and advantages of the invention will become apparent to the reader of the following specification.

In the drawings:

Figure 1 represents a side elevational view of the entire apparatus.

Figure 2 is a top plan view of the circulating tube.

Figure 3 is a vertical sectional view through the circulating tube taken substantially on a line 3-3 of Figure 2.

Figure 4 is a horizontal sectional view through the lower portion of the circulatin tube taken substantially on the line 4-4 of Figure Figure 5 is a horizontal sectional view taken substantially on the line 5-5 of Figure 1.

Figure 6 is a front elevational view of the recorder and signal means.

Figure '7 is a side elevational view of a slightly modified form of the invention.

Figure 8 is a side elevational view of another modification of the present invention.

Referring to the drawings wherein like numerals designate like parts it can be seen that reference character A generally refers to the circulating tube while referenc character B denotes the recorder. 7

Briefly, the method used is to permit a part or the return floW of mud from the well to pass through the circulating tube assembly A in such a manner that at any given point in this tube a pressure will be caused by the wei ht of the mud or drilling fluid at all times. This is accomplished by the use of an upright tube 3 of certain minimum dimensions having a fluid inlet and overflow, a point of pressure measuring and a fluid outlet. The fluid outlet will be at a point sufficiently below the fluid inlet to provide a flow through the tube due to a difference in head between the points. This tube is placed at a suitable point in the mud system to receive the mud and discharge it with a minimum of inconvenience. The most convenient place is generally in or immediately adjacent to the mud pits. The mud from the well necessary to keep the device overflowing canbe diverted from the mud return channel into it and passing through it be discharged into the mud pits. Where vertical distance between the mouth of the well and the surface of the mud pits is slight, the device may be partially submerged in the mud pit. The apparatus can also be used to measure the specific weight of the fluid being introduced into the well by being placed in the flow system so as to take fluid before the fluid passes through the pumps, or to take fluid that has been bled ofi after passing through the pumps.

In carrying out the present invention, mud fluid is introduced into the device at the inlet I which is of funnel shape as substantially shown in Figure 1, at a suflicient rate to maintain a constant overflow through the inlet overflow lip 2. The mud then passes down through the tube 3 and out of the tube at the outlet slot 4. The outlet may either be of a reduced area to give an accelerated velocity at point of outlet as a precaution against clogging and as illustrated in Figure 8 and denoted by the reference character 4a. Furthermore, as shown in Figure '7, the outlet may be as shown and denoted by reference character 4b. In this pipe 4b a butterfly valve 20 or any suitable valve is employed therein and controlled by the rod 2| in a manner similar to the control of the gate in the preferred form of the invention shown in Figure 1.

The gate 22 in the form of the invention shown in Figure 1 is of arcuate shape, or a curvature height. This column of mud-fluid in tube 3 will; exert a pressure at the air bell 5 equal to the head of fluid at that point. Since the length of the tube 3 is constant, this head will be directly proportional to the weight or specific'gravity ofthe tures, oil-mud mixtures, cement slurries, cementinud jel slurries, or any of the other various mixtures used in the drilling or conditioning of well fluid and the pressure in air bell 5 will be pro- I portional to the specific weight of the'mud.

As the specific gravity and the correspondingrelatively small compared to that of the air bell 5, or, not over the ratio of one-fourthto' one. This transmitted pressure will then be :relatively thesame atany point it may be measured. The measurement of this transmitted pressure can be by any conventional pressure indicating or/and recording device- 7; although it must be both delicate and sensitive. This pressure responsive element can be either a Bourdon tube, Sylphon bellows or a metallic diaphragm similar to an aneroid barometer type. A source of air pressure is provided by a bulb-or small air pump 3 through a valve manifold 9 so that the capillary tube 6 may be closed or receive-air as desired. The purpose of this air injector means 8--9- is 7 to replenishthe air in the air hell 5 if it should become exhausted and to testthe pressure recordings which may be done by forcing air into the system through the air pumpand valves 9-9 until air is forced out ofthe bottom of the air bell 5, and out of the tube outletv l oruntil the bores.

In order to call attention of the operator or driller to excesssive or deficient drilling mud weight, an alarm system is incorporated. Batteries H provide electric energy which is conducted to the measuring device Ill, indicating arml2, which with excessive mud weight contacts post l3 closing circuit through alarm M; or with deficient weight contacts post l5, thus closing circuit'through alarm I5.

While the foregoing specification sets forth the invention in specific terms, it is to be understood thatnumerous changes in the shape, size and materials may be'resorted to without departing from the spirit and scope of the invention as claimed hereinafter.

Having described the invention, what is claimed as new is:

1. An apparatus of the character described comprising a vertical tube having an inlet at its upper end, and an overflow designed with its horizontal dimension substantially greater than its vertical located adjacent to the point of inlet, a controllable outlet at its lower end, an air bell communicating with the lower portion of the tube, an air line extending from the bell, a meas-v uring and recording device responsive to pressure with which the line communicates, and a pump in said air line. -2. An apparatus of the character described comprising a vertical tube having an inlet at its upper end, and an overflow designed with its horizontal dimension substantially greater than its vertical located adjacent to the point of inlet, a controllable outlet at its lower end, an air bell communicating with the lower portion of the tube and an air line extending from the bell, a measuring and recording device responsive to pressure with which the line communicates, and means of adding or exhausting air from said air line.

OSCAR E. STONER. 

